Tail call optimization improvements:

Move platform independent code (lowering of possibly overwritten
arguments, check for tail call optimization eligibility) from
target X86ISelectionLowering.cpp to TargetLowering.h and
SelectionDAGISel.cpp.

Initial PowerPC tail call implementation:

Support ppc32 implemented and tested (passes my tests and
test-suite llvm-test).  
Support ppc64 implemented and half tested (passes my tests).
On ppc tail call optimization is performed if 
  caller and callee are fastcc
  call is a tail call (in tail call position, call followed by ret)
  no variable argument lists or byval arguments
  option -tailcallopt is enabled
Supported:
 * non pic tail calls on linux/darwin
 * module-local tail calls on linux(PIC/GOT)/darwin(PIC)
 * inter-module tail calls on darwin(PIC)
If constraints are not met a normal call will be emitted.

A test checking the argument lowering behaviour on x86-64 was added.

llvm-svn: 50477

3 files changed, 36 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/PowerPC/tailcall1-64.ll b/llvm/test/CodeGen/PowerPC/tailcall1-64.ll
new file mode 100644
index 00000000000..f39b40bdab8
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/tailcall1-64.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | llc -march=ppc64 -tailcallopt | grep TC_RETURNd8
+define fastcc i32 @tailcallee(i32 %a1, i32 %a2, i32 %a3, i32 %a4) {
+entry:
+	ret i32 %a3
+}
+
+define fastcc i32 @tailcaller(i32 %in1, i32 %in2) {
+entry:
+	%tmp11 = tail call fastcc i32 @tailcallee( i32 %in1, i32 %in2, i32 %in1, i32 %in2 )		; <i32> [#uses=1]
+	ret i32 %tmp11
+}
diff --git a/llvm/test/CodeGen/PowerPC/tailcall1.ll b/llvm/test/CodeGen/PowerPC/tailcall1.ll
new file mode 100644
index 00000000000..1fc4b94ddcf
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/tailcall1.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | llc -march=ppc32 -tailcallopt | grep TC_RETURN
+define fastcc i32 @tailcallee(i32 %a1, i32 %a2, i32 %a3, i32 %a4) {
+entry:
+	ret i32 %a3
+}
+
+define fastcc i32 @tailcaller(i32 %in1, i32 %in2) {
+entry:
+	%tmp11 = tail call fastcc i32 @tailcallee( i32 %in1, i32 %in2, i32 %in1, i32 %in2 )		; <i32> [#uses=1]
+	ret i32 %tmp11
+}
diff --git a/llvm/test/CodeGen/PowerPC/tailcallpic1.ll b/llvm/test/CodeGen/PowerPC/tailcallpic1.ll
new file mode 100644
index 00000000000..678d366fb6a
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/tailcallpic1.ll
@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | llc  -tailcallopt -mtriple=powerpc-apple-darwin -relocation-model=pic | grep TC_RETURN
+
+
+
+define protected fastcc i32 @tailcallee(i32 %a1, i32 %a2, i32 %a3, i32 %a4) {
+entry:
+	ret i32 %a3
+}
+
+define fastcc i32 @tailcaller(i32 %in1, i32 %in2) {
+entry:
+	%tmp11 = tail call fastcc i32 @tailcallee( i32 %in1, i32 %in2, i32 %in1, i32 %in2 )		; <i32> [#uses=1]
+	ret i32 %tmp11
+}